extrinsic resistance
1.The study is aimed to screen the varies insect-resistance clones of the triploid of Chinese white poplar through feeding Lymantriadispar (Linnaeus) and Clostera anachoreta(Fabricius) test, and to validate the insect-resistance character through the test of molecule biology detection, the rule of the expression of extrinsic gene, the persistence of insect-resistance, the detoxifcation enzyme and digestive enzyme of the insects and micro-observation of the midgut.
2.Nominal growth resistance of long fatigue cracks for alu-minum-lithium alloys 2090 and 8090 is superior to that for alloys 7075 and 2024, respectively,which is attributed to crack closure effect in near-threshold zone and to detamination toughnesseffect in Ⅲ zone,and extrinsic toughness effect in Paris zone comes from the unite effect of crackclosure and detamination toughness.
